Rotatable bark-remover cutters and knives



May 10, 1955 H. H. FALKMAN ET AL ROTATABLE BARK-REMOVE]? CUTTERS ANDKNIVES 4 Sheets-Sheet 1 Original Filed April 10 1951 km mm O p A Oh W W4 NW MIMI m WM A m. WM E V .0 N"

m 7 a, UJT\\ May 10, 1955 H. H. FALKMAN ET AL ROTATABLE BARK-REMOVERCUTTER-S AND KNIVES 4 Sheets-Sheet 2 Original Filed April 10 1951 May10, 1955 H. H. FALKMAN ET AL 2,707,979

ROTATABLE BARK-REMOVER CUTTERS AND KNIVES Original Filed April 10 1951 4Sheets-Sheet 3 T4 Fig;3 i

y 1955 H. H. FALKMAN ETAL ROTATABLE BARK-REMOVER CUTTERS AND KNIVES 4Sheets-Sheet 4 Original Filed April 10 1951 United States PatentROTATABLE BARK-REMOVER CUTTERS AND KNIVES Hans Hugo Falkman,Johanneshov, Nial Torbjiirn Karln, Stockholm, and Erik Magnus Olsson,Nacka, Sweden, assignors to Aktiebolaget Atlas Diesel, Nacka, Sweden, acorporation of Sweden Original application April 10, 1951, Serial No.220,154. Divided and this application July 8, 1952, Serial No. 297,636

Claims priority, application Sweden April 11, 1950 6 Claims. (Cl.144--208) This application is a division of our copending applicationSerial No. 220,154, filed April 10, 1951.

The present invention relates to bark cutting machines comprising arotatable cutter and the invention is particularly related to such barkcutting machines which are moved by hand along a log with the axis ofrotation of the cutter disposed transversely to the longitudinal axis ofthe log. The invention also relates to cutters and knives for such barkcutting machines. j

One object of the invention is to provide a bark cutting machine whichhas low weight and is of simple and rigid construction and in whichample space is provided for the passage of the chips produced during thecutting operation. A further object of the invention is to provide acutting machine in which the cutter comprises any number of fixed kniveswith a shape producing a substantially V-shaped out which within widelimits corresponds rather well to a portion of the periphery of logs ofdifferent diameters. A still further object of the invention is toprovide simple, rigid and light cutters and knives for bark cuttingmachines which are simple in manufacture.

In the accompanying drawings one embodiment of a bark cutting machineaccording to the invention, a cutter for such a machine, and profilesproduced by such a cutter upon operation on logs of three differentdiameters are illustrated by way of example, it being understood,however, that these showings are by no means limiting for the inventionwhich may be varied in different ways within the scope of the claims.Fig. 1 is a side elevation of a bark cutting machine according to theinvention, and Fig. 2 is an end elevation of said machine, partly insection, as indicated by the line 2-2 in Fig. 1. Fig. 3 is a fragmentaryfront elevation on a larger scale of a cutter for a machine according toFigs. 1 and 2, one knife only of said cutter being illustrated in thefigure and one of the knife supports being broken away and shown partlyin section. Fig. 4 is a composite end elevation and partial crosssection of the cutter, as taken on the line 4-4 of Fig. 3, but includesthe knife which was omitted in Fig. 3. Figs. 5, 6 and 7 illustrate incross section cuts produced by the cutter according to Figs. 3 and 4 inthe bark of logs of three different diameters.

The bark cutting machine according to Figs. 1 and 2 is a machine drivenhand tool for operation longitudinally of a log with the axis ofrotation of the cutter directed transversely to the longitudinal axis ofthe log. The machine consists of a frame or housing 1 in which a cuttergenerally designated by the reference numeral 2 is rotatably journalled.The housing 1 forms a bracket 3 for carrying a motor 4 which may be acompressed air driven motor, an internal combustion motor, an electricmotor, or any other suitable motor. The shaft 5 of the motor 4 carries apulley 6 for a V-belt 7 which drives a wheel 8 secured on a shaft 17 ofthe cutter 2. The V-belt drive is protected by a cover (not shown) whichis carried by the housing 1. The housing covers and protects the cutter2 and is provided with handles 10 and 11 disposed behind and in front ofthe cutter 2 when looking in the direction of feed of the machine. Inthe embodiment illustrated in Figs. 1 and 2 the motor 4 is a compressedair driven motor, and a supply conduit 12 for compressed air is carriedthrough the handlell) to the motor. For controlling the operation of themotor a main valve of conventional design and having an operating lever13 is disposed in the handle 10. The motor 4 has asupport 14 designed soas to permit adjustment of the tension of the V-belt 7, and for thispurpose the support 14 has two lugs embracing the bracket 3 on thecutter housing 1. The support 14 is secured to the bracket 3 by means ofscrews 15 extending through elongated openings 16 in the lugs of thesupport 14 thereby permitting adjustment of the tension of the V-belt 7.

The cutter 2 provided in the bark cutting machine according to Figs. 1and 2 comprises the shaft 17 forming the hub portion of the cutter, twotransverse walls 18 which may be welded onto the shaft or secured to theshaft in any other way or made integral with the shaft, as indicated inFigs. 3 and 4, and two knives 21 carried by the transverse walls and theshaft. The transverse walls 18 are provided with slots 19 formed in theleading edge 20 of the walls, and in which slots the knives 21 areinserted. The knives 21 extend along the hub portion or shaft 17 of thecutter at such a distance that a large free area for the passage of thechips is provided between the knives and the hub portion. The knives 21are formed by blanks of open V-shape cut out from tubular material, andthe knives consequently form por tions of cylinders, as is obvious fromFig. 4. The knives have an edge curve 22 which forms an open Vpreferably having about 140 angle between the shanks and rounded at thebottom of the V as indicated at 23. The curve 23 is formed so that thecut produced by the knife 21 fits the curvature of the smallest diameterof the log for which the cutter is intended. At the free ends of theshanks of the V the edge of the knife forms portions 24 substantiallyparallel to the axis of the cutter and extending substantially along ageneratrix of the cylinder. Two slots 25 are provided in the trailingedge of each of the knives 21, the spacing of the slots corresponding tothe distance between the two transverse walls 18 so that the slots 25will register with the slots 19 of the transverse walls 18 to formjoints which engage one another like two forks and thus lock the knivesin the transverse walls against relative movement in two directions.Oppositely extending and interiorly threaded abutments 26 are formedcentrally on the hub portion 17, and central portions of the trailingedges of the knives 21. are apertured to receive screws 45 which threadinto the abutments and thus lock the knives 21 and the trans verse walls18 against relative movement in a third direction. The fastening pointsof the knives form a triangle, and a very eilicient and simple fasteningof the knives is obtained in this manner, and such fastening alsosimplies the exchange of knives. As obvious from Fig. 3 the edge curves22 and 23, and the straight edge portions 24 of the knives 21 are madesymmetrical relative to a plane perpendicular to the shaft 17 andcontaining the common axis of the threaded abutments 26.

In order to guide the bark cutting machine along the logs the machine isprovided with guiding means comprising four supporting and guide wheels27 journaled at the ends of transverse levers 28 swinging on trunnions29 having springs 30 provided thereon which act to force the levers 28with the guide wheels 27 against a log, for instance the log 46indicated in cross section in Fig. 2. The levers 28 are provided withupwardly directed arms 32 pivotally connected by pins 32 to pairs oflinks 33 having common pins 34 guided in vertical slots 35 in plates 36secured to the housing 1. The guiding of the pins 34 in the slots 35results in forced guiding of the wheels 27 causing both wheels of eachpair to take symmetric relative positions one on each side of thetransverse plane of symmetry of the cutter 2. The bark cutting machineis furthermore provided with a supporting roller 37 journaled at therear end of the machine and forming a nonyielding support on which themachine may be swung during operation in order to modify the depth ofthe cut which is obviously increased when the machine is pressed withincreased force against the log by means of the handle 11.

Figs. -7 illustrate the profiles removed by the described cutter uponoperation on logs of different diameters. The log 38 according to Fig. 5has a diameter of about inches, whereas the log 39 in Fig. 6 has adiameter of about 6 inches, and the log 40 in Fig. 7 a diameter of about3 inches. In said figures, 41, 42 and 43, respectively, indicate thebark, the main part of which it is desired to remove. 44 indicates thecurve or profile cut away by the cutter 2, and it is obvious from Figs.57 that said curve corresponds sufficiently close to the curvature oflogs of different diameters to cause a small portion only of the bark tobe left remaining on the log.

The bark cutting machine above described and illustrated in the drawingsoperates in the following manner:

During barking the machine is placed with the axis of rotation of thecutter 2 directed transversely to the longitudinal axis of the log. Aslight pressure towards the log is applied on the machine so that theroller 37 and the cutter 2 engage the log. The wheels 27 are thenpressed symmetrically outwardly so that the machine rides on the logwith the plane of symmetry of the cutter coinciding with the plane 47containing the common axis of threaded abutments 26, 26 and thelongitudinal axis of the log indicated in Figs. 2, 5, 6 and 7. Upondepres- I sion of the lever 13 compressed air is supplied to the motor 4so that the motor rotates and the cutter starts to work. By using theroller 37 as a pivot or fulcrum the operator may control the depth ofthe cut by pressing the handle 11 more or less against the log. Theweight of the machine and/or the pressure by means of which it ispressed against the log together with the guiding wheels 27 causes theplane of symmetry of the cutter automatically to substantially coincidewith the plane 47 through the longitudinal axis of the log irrespectiveof the diameter of the log.

The invention also includes the special cutter and knives employed inthe bark cutting machine according to the invention. Naturally, thecutters may comprise any number of knives, and the knives may be formedfrom substantially plane or other blanks. The knives may also beotherwise shaped than hereinabove described and illustrated on thedrawings, and for operation on logs of larger dimensions, for instance,the angle between the shanks of the V-edge may vary up to about 180. Theguiding wheels 27 and the roller 37 may be replaced by suitable guidingsurfaces or other guiding means on which the machine slides. Sometimesthe guiding wheels may be dispensed with. The handle 11 may be replacedby a transverse handle.

What we claim is:

1. A bark cutting machine comprising a frame, a cutter mechanismrotatably journaled in said frame, a shaft in said cutter mechanism,knives forming parts of said cutter mechanism and fixed to said shaftand extending freely along the axis of rotation of said cutter mechanismat such a distance from said axis that a great free area for the passageof chips is provided between said knives and said shaft, and means forsecuring the knives in fixed relation to the shaft at three points ofeach knife disposed so as to form the corners of a triangle viewed whenlooking toward the axis of rotation of the cutter mechanism.

2. A bark cutting machine comprising a frame, a cutter mechanismrotatably journaled in said frame, a shaft having hub portions at bothends of said cutter mechanism, knives forming parts of said cuttermechanism and fixed to transverse walls on said hub portions andextending freely along the axis of rotation of said cutter mechanism atsuch a distance from said axis that a great free area for the passage ofchips is provided between said knives and said shaft, said transversewalls on said hub portions having slots for receiving portions of saidknives, and screw means between said walls for fixing a further portionof the knives to the shaft, said slots and screw means for eachknifebeing disposed so as to form a V.

3. A bark cutter knife for rotary mounting in a bark cutting machineincluding a blade formed as a portion of a cylinder and having the shapeof a V-shaped wing viewed when looking along a radius of said cylinder,said blade having a cutting edge formed along the inside of said V-shaped wing with an edge curve comprising a rounded central portionmerging into substantially straight portions forming the shanks of the Vwhich at their outer ends merge into portions extending substantiallyalong a generatrix of the cylinder.

4. A bark cutting machine comprising a frame, a cutter mechanismrotatably journaled in said frame, a shaft forming a part of said cuttermechanism, at least two supports on said shaft projecting transverselyof the shaft, knives fixed relative to said supports and extendingfreely along the shaft between the supports at such a distance from saidshaft that a great free area for the passage of chips is providedbetween said knives and said shaft, each knife being formed as a portionof a cylinder and having the shape of a V-shaped wing fixed to saidsupports a the end portions of the wing.

5. A bark cutting machine comprising a frame, a cutter mechanismrotatably journaled in said frame, a shaft having hub portions at bothends of said cutter mechanism, knives forming parts of said cuttermechanism and fixed to transverse walls on said hub portions at such adistance from the axis of rotation of said cutter mechanism that a greatfree area for the passage of chips is provided between said knives andsaid shaft, said transverse walls on said hub portions having slots forreceiving portions of the knives, and slots in said knives for receivingportions of said transverse walls to form an interlock between saidknives and said transverse walls to keep the knives in fixed relation tothe hub portions.

6. A bark cutter assembly comprising a cutter shaft formed for rotarymounting in a machine, at least three supports extending radially fromsaid shaft and disposed so as to form the corners of a polygon viewedwhen looking toward one side of said shaft, and at least one knife inthe cutter assembly secured to said supports in spaced relation to saidshaft to provide a great free area for the passage of chips between thesupports and between the shaft and said knife.

References Cited in the file of this patent UNITED STATES PATENTS1,893,016 Brown Jan. 3, 1933 I FOREIGN PATENTS 38,655 Sweden Apr. 14,1915 54,893 Sweden June 27, 1923 526,647 Germany June 8, 1931 908,030France Aug. 6, 1945 117,415 Sweden Oct. 15, 1946

